The role of prefrontal cortex in visuo-spatial planning: a repetitive TMS study

Abstract

The visuo-spatial planning process is based on an "opportunistic" combination of heuristics and strategies, carried out in small units during the execution of plans. In order to investigate the functional role of the prefrontal cortex in heuristic switching, 42 healthy controls performed a labyrinth crossing task (the Maps Test). During this computerized version of the Travelling Salesperson Problem, subjects had to decide which order of locations optimizes total travel time and distance. This task was performed with and without 1 Hz repetitive transcranial magnetic stimulation (rTMS), which exerts an inhibitory action on the targeted area, applied during the task over bilateral frontal sites (active stimulation) and parieto-occipital site (sham stimulation). Only repetitive bilateral rTMS over F3 and F4 significantly decreased the number of strategies with changes of heuristics, and increased the number of movements required to solve the task. This behaviour contrasts with the performance of healthy subjects in the planning task, but is consistent with the performance of frontal traumatic brain injury patients. The results indicate that, in a visuo-spatial problem-solving task, the prefrontal cortex is involved in the switching between heuristics during the execution of a plan.

Human Performance on the Traveling Salesman and Related Problems: A Review

“…Participants use keyboard arrow keys to move a cursor along roads to indicate a path between points. Using the Maps task, Basso and colleagues have reported results indicating that people may switch among several heuristics during the process of a single solution, and that inhibiting switching results in performance decrements (Basso et al, 2006;Cutini et al, 2008). Recent research from this group has also reported gender differences (Cazzato et al, 2010).…”

“…Basso, Bisiacchi, and colleagues have used a variation of the standard TSP referred to as the Maps test. The main purpose of the research has been to identify how heuristics are used by human solvers and how this may be affected by brain damage or other forms of functional impairment (Basso et al, 2001;Basso et al, 2006). These latter findings will be described later, while in the present section we will describe the task itself and some…”

“…Normal participants showed a relatively constant planning time at each step, whereas CHI participants showed much greater variability. Basso et al (2006) used the same task to compare the performance of normal adults operating with and without repetitive transcranial magnetic stimulation (rTMS), which is considered to exert inhibitory effects on the targeted brain region. The experiment used a counterbalanced within subjects design where half of the rTMS trials were applied to the frontal regions (areas F3 and F4-the active condition) and half to the left parieto-occipital position (area PO3-the placebo condition).…”

Consumer neuroscience: an overview of an emerging discipline with implications for consumer policy

“…Notwithstanding potential concerns related to TMS, it has the potential to better explain the occurrence of phenomena in consumer research: an example of a TMS study that would have relevance for consumer research is an experiment conducted by Basso et al (2006). They used repetitive TMS to investigate the role of the prefrontal cortex in visuospatial planning.…”

Indentations and Starting Points in Traveling Sales Tour Problems: Implications for Theory

“…In recent years cognitive scientists have begun to examine human performance in optimization tasks and, although still in its infancy, this new research area has attracted the attention of researchers working in vision (Findlay & Brown, 2006), memory (Kong, Schunn, & Wallstrom, 2010), decision making (Ragni & Löffler, 2010), clinical neuroscience (Basso et al, 2006) and comparative psychology (Gibson, Wasserman, & Kamil, 2007). Preliminary findings reported in the psychological literature indicated that untrained human subjects can quickly produce optimal or near-optimal solutions to TSPs, and often outperform simple approximating algorithms, such as the nearest neighbour procedure (MacGregor & Ormerod, 1996).…”